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Biomedical subjects

J Pollock

Publications and source records attributed to J Pollock.

At least 73 records · Page 4Linked to original sources
PubMed1985

Inhibition of flank-marking behavior in golden hamsters by microinjection of a vasopressin antagonist into the hypothalamus.

Microinjection of arginine-vasopressin (AVP) into the medial preoptic area of the hypothalamus of the hamster stimulates flank marking, a complex stereotypic motor behavior involved in olfactory communication. Microinjection of an antagonist of AVP, [1-deaminopenicillamine-2-(O-methyl)-tyrosine]arginine-vasopressin, into the same site blocks both the effect of microinjected AVP as well as the natural flank-marking behavior normally elicited by placing a hamster into the recently vacated home cage of another hamster. This finding supports the notion that AVP is a transmitter in the expression of flank marking.

Animal Communication↗
PubMed1984

Yersinia enterocolitica infection in breeding colonies of ruffed lemurs.

Two outbreaks of yersiniosis caused by Yersinia enterocolitica occurred in breeding colonies of red ruffed lemurs (Varecia variegata rubra) and black and white ruffed lemurs (Varecia variegata variegata) housed in outdoor enclosures during the winter breeding season and spring birth season, respectively. Seven of 11 animals at risk in the combined outbreaks became ill, and 3 died of acute to chronic infection. Clinical signs included anorexia, lethargy, diarrhea, abdominal pain, and hyperpyrexia. Necropsy findings included ulcerative enterocolitis and multifocal necrosis and abscess formation in mesenteric lymph nodes, liver, spleen, kidneys, and lungs. Histologically, lesions were characterized by necrotizing inflammation containing masses of basophilic bacteria. Yersinia enterocolitica serotype 0:2 was isolated from lesions. Neomycin sulfate given orally and chloramphenicol given intramuscularly were effective in treatment early in the course of the disease or in mild cases. In severe cases, lemurs did not respond to antibiotic and fluid therapy. Exposure to soil contaminated with infected rodent feces, stress, and behavioral factors in the ruffed lemur species are believed to have precipitated the infection.

Animals↗
PubMed1983

Rh immunization in Manitoba: progress in prevention and management.

For two decades the perinatal mortality caused by erythroblastosis has been decreasing in Manitoba. The improved management of Rh-immunized pregnancies has lowered the death rate among affected infants from 10.8% to 3.4%, while the prevention of Rh immunization has reduced its incidence from 9.1 to 2.2 per 1000 total births. In its first 6 years and 8 months Manitoba's antenatal prophylaxis program, in which immunoglobulin is administered to Rh-negative women at 28 weeks' gestation, reduced the incidence of Rh immunization during pregnancy by 93%. In combination with post-abortion and postpartum prophylaxis the antenatal treatment has provided a protection rate of 98.6% among primigravidas at risk. Further improvements are expected.

Erythroblastosis, Fetal↗
PubMed1980

Calcification in porcine xenograft valves in children.

Calcification developed in the degenerating collagen of the cusps of three porcine xenograft heart valves implanted in children for less than 4 years. The morphologic features and effects of this calcification are presented. Calcification of porcine xenografts seems to occur more frequently and at an earlier stage after insertion in children than in adults. Host factors, possibly related to calcium homeostasis, may promote calcification; hence, these valves may not be appropriate for use in children.

Adolescent↗
PubMed1979

Computed tomography in primary reticulum cell sarcoma of the brain.

The CT findings in 16 patients with histologically proved primary central nervous system (CNS) reticulum cell sarcoma (RCS) showed this malignancy to have predilection for the basal ganglia and thalamus, the periventricular white matter, the corpus callosum, and the vermis cerebelli. In 43% of patients with untreated tumor it presented as multifocal lesions; in each of these patients the basal ganglia were involved in conjuction with another site. In the other 57% of patients with untreated tumor presenting as solitary lesions the basal ganglia, the corpus callosum, and the frontal lobe were sites of predilection. Such solitary lesions may be indistinguishable from other tumors. Contrast enhancement of RCS was characteristically homogeneous with rare lucency, even in very large lesions.

Adolescent↗
PubMed1978

Malignant melanoma metastatic to the central nervous system.

The CT appearance of metastatic malignant melanoma is varied, but it can show features suggesting the correct diagnosis. Intracerebral hemorrhage alone, associated with an adjacent tumor nodule or mixed diffusely with a tumor, occurred in 10 of 33 patients. Identification of a tumor nodule is important, since it may be the site of recurrent hemorrhage if not removed completely at surgery. Unusual presentations such as meningeal carcinomatosis and lesions simulating primary gliomas also occurred.

Adult↗
PubMed1978

Pitfalls of the alcohol dehydrogenase procedure for the emergency assay of alcohol: a case study of isopropanol overdose.

We describe a case of ethanol and isopropanol ingestion that resulted in coma. The concentration of ethanol and isopropanol was 0.90 and 1.65 g/liter in serum and 3.12 and 5.34 g/liter in gastric contents. With an enzymatic (alcohol dehydrogenase) method for ethanol determination we obtained erroneous analytical results. Because of partial cross reactivity with isopropanol, ethanol concentration was overestimated and total alcohol (i.e., the contribution of isopropanol) was underestimated. This was recognized by measuring serum osmolality. Differences between measured and calculated serum osmolality that are not accounted for by the serum ethanol concentration as determined by an enzymatic ethanol method must be further investigated by specific methods to see if other alcohols are present.

1-Propanol↗
PubMed1977

Rh isoimmunization, Manitoba, 1963-75.

The number of Rh-isoimmunized pregnancies in Manitoba has been reduced from 223 and 228 in the years ending Oct. 31, 1963 and 1964 to 60 and 62 in the years ending Oct. 31, 1974 and 1975. The number per 1000 total births in the same years has decreased from 10.0 and 10.6 to 3.4 and 3.5 Perinatal mortality rates in those years decreased from 13.8 amd 15.7% to 0 and 2.2%, respectively. The number of perinatal deaths has been reduced from 55 in the first 2 years reported to 1 in the last 2 years. Among the 121 isoimmunized women pregnant in the 2-year period ending Oct. 31, 1975, isoimmunization was due to failure to give Rh immune globulin after delivery in 33 and failure to give it during pregnancy in 48. Of the remaining 40, 37 were immunized before Rh immune globulin became available. Complete prevention of Rh isoimmunization and therefore of all perinatal deaths from Rh erythroblastosis can only be achieved through universal Rh testing prenatally and immediately after delivery, and institution of an antenatal Rh prophylaxis program.

Antibody Formation↗
PubMed1977

Relationship of serum theophylline concentration to inhibition of exercise-induced bronchospasm and comparison with cromolyn.

Exercise-induced bronchospasm was induced by treadmill running in 12 children on two days preceding either inhaled cromolyn sodium (Intal) or oral theophylline (Slo-Phyllin tablets), 7.5 mg/kg, administered in a double-blind manner. A second exercise period identical to the first followed two hours later; the medication administration had been timed so that the second exercise stress followed two hours after theophylline administration and 15 minutes following cromolyn administration. The patients subsequently were exercised twice more at two-hour intervals on both days. Blood was drawn from serum theophylline measurement immediately after each of the exercise periods. There was little demonstrable exercise-induced bronchospasm resulting from the first postmedication exercise period following theophylline administration. The two subsequent exercise periods were associated with some return of postexercise bronchospasm. The degree of inhibition of exercise-induced bronchospasm correlated with serum theophylline levels that averaged 16, 13, and 10 microgram/ml at two, four and six hours after the theophylline dose (mean Spearman rank correlation coefficient = .71, P less than .01). The effect of cromolyn in suppression exercise-induced bronchospasm that matched or excelled that seen with theophylline.

Adolescent↗
PubMed1975

An error in Rh testing in pregnancy.

Anti-D (anti-Rho) in the blood of two Rh-negative pregnant women was believed to be due to active immunization. In the first case, however, antibodies were no longer detectable 2 weeks later. In the second case they disappeared by the end of 31 weeks. It was discovered that both women had been given immune globulin (human) because of exposure to rubella. The globulin given to the first woman probably contained about 0.1 mug of anti-D per ml; that given to the second probably contained about 0.6 mug of anti-D per ml. Both babies were O Rh-positive. Both women were given Rh immune globulin after delivery. Both have completed a further pregnancy and no anti-D has been found on many tests. In tests carried out in 1971 all samples of immune globulin (human) examined contained anti-D, but usually in inconsequential trace amounts.

Diagnostic Errors↗
PubMed1970

The effect of anti-D IgG on D-positive recipients.

When one standard prophylactic dose of anti-Rh(D) immunoglobulin (Connaught) (and in one case two doses) was injected into 15 D-positive volunteers it caused no reaction and no measurable alteration in readings of hemoglobin, hematocrit, reticulocytes or bilirubin, although some of the volunteers briefly became weakly direct Coombs'-positive. It is argued that since any isohemagglutinin that may contaminate anti-D IgG must be much less in amount than the anti-D it contains, the contaminating antibody cannot carry a greater potential for harm to a recipient having the corresponding antigen than the anti-D for a D-positive recipient, which is zero. It is suggested that the presence of anti-DC or G in so-called anti-Rh(D) IgG may, in fact, be a mark of excellence. The application of these facts to selection of plasma donors and to tests required before giving prophylactic treatment to women is briefly stated.

Adult↗